biological membranes Flashcards
which direction do the molecules spread in diffusion?
from areas of higher concentration to lower concentration
what 3 things affect the rate of diffusion?
surface area, difference in concentration,
what are lysed, normal and crenation in blood cells?
lysed- the net movement into the cell is more dilute & the cell wall bursts if concentration of blood is too dilute, normal- same concentration in and out of cell, crenation- inside has more water than outside of cell so H2O moves out
what happens in a plant cell, why doesn’t it burst?
the plant cells swell, but cant burst due to the cell wall, the vacuole just gets very large
what is endocytosis?
bulk transport into the cell, the membrane folds into a pouch surrounding the cell forming a vesicle
what is exocytosis?
cell waste or cell products, moves towards the cell membrane and fuses to release cotents by exocytosis
in active transport which direction do the molecules move?
low to high and this requires ATP
what does facilitated diffusion use?
channel and carrier proteins
does active transport move substances towards or against the concentration gradient
against
how do cells take in substances
endocytosis
how do cells secrete
exocytosis
what is needed for endocytosis and exocytosis
ATP
what is osmosis?
diffusion of water molecules
state in order the stages of mitosis
(interphase), prophase,
Metaphase anaphase, telophase, (cytokinesis)
what does meiosis produce
gametes for sexual reproduction
where do the chromatids cross over
prophase 1
how does meiosis produce genetically different cells?
crossing over of chromatids- different alleles and independent assortment of chromosomes- when the homologous pairs line up its random so the 4 daughter cells have different combinations of the parental chromosomes
what are stem cells?
unspecialised cells
what do cells in bone marrow differentiate into
neutrophils and erythrocytes (red and white blood cells)
how might stem cells be used to treat Parkinson’s?
transplanted stem cells are hoped to reproduce the dopamine producing receptors
how are neutrophils and erythrocytes specialised?
neutrophils- flexible shape allows them to engulf, many lysosomes in cytoplasm containing digestive enzymes to break down invading particles, erythrocytes- biconcave shape for larger SA for gas exchange, no nucleus so more room for haemoglobin
how are epithelial cells and sperm cells specialised
epithelial cells - have cilia that beat to move particles away, squamous epithelium are very thin in the lungs for gas exchange, sperm cells- have flagellum so they can swim to the egg, the head had digestive enzymes to penetrate the egg
what is meant by tissue
a group of cells that are specialised to work together to carry put a particular function
what are the 4 types of animal tissue?
squamous epithelium, ciliated epithelium, muscle tissue, cartilage
what are the 2 types of plant tissue
xylem and phloem
what is an organ
a group of different tissues that work together to perform a particular function
give an organ found in a plant and one found in an animal
lungs and leaves
what makes up and organ system, give an example
different organs, the respiratory system
